Ted,
I used new rubbers and using Ken's method, I fitted the airbox first but without the intake rubbers, then the carbs without clips in case I needed some wiggling. Then I massaged the new rubbers with a small amount of silicone grease inside and out. I fitted numbers 2 and 3 rubbers first and they squidged in very easily and I put those clips loosely in place. 1 and 4 were even easier. Then I fitted and did up all 12 clips.
Ian